A headlight, especially for motor vehicles, contains at least one optical system comprising a powerful light source and optical elements. The light source emits light rays and the optical elements represent a system of refractive and reflective surfaces, interfaces of optical environments and diaphragms that influence the direction of light rays within the creation of the output light trace.
In modern headlights of motor vehicles, light sources consisting of LED light units are frequently used. An advantage of the LED light units is their long service life and compact dimensions. The documents JP2013252821A, AT512864B1, and US20110267455A1 describe light devices enabling creation of unlit or less lit parts of the carriageway as a combination of the low and high beam of light. During a drive of the motor vehicle with the high beam on, individual light units or their groups or rows can be optionally switched off to produce a dark unlit part in the light pattern on the carriageway in the place where the camera detects an oncoming vehicle. However, LED light units individually have a low light output, which can be increased by using a high number of LED light sources, but directing light beams from a higher number of LED light sources and creating a suitable light pattern is difficult and thus it still remains a technical problem.
The document US20130021810A1 discloses a lamp of a motor vehicle with a number of LED light sources that are arranged in a two-dimensional planar matrix in two directions, and their light intensity is adjustable depending on the position of a light element in one and/or the other direction. The intensity of the LED light sources can be adjusted or controlled variably by means of activation and deactivation of individual LED light sources, depending on the particular need of the area in front of the vehicle. To create a sufficiently large dark unlit part in the place where the camera detects an oncoming vehicle, the LED light sources are switched off and on in sections in the shape of vertical stripes; however, their margins are diffused and no suitable technical means is provided to control the sharpness of the edges of the vertical stripes and to create a sharp light image.
The document CZ20150092 discloses a light device that comprises a light source consisting of a system of light units and collimating optical elements for concentration of rays of the light units to the direction of the light axis of the vehicle x, where between the collimating optical elements and the output, lens diaphragms are arranged that are fitted with sets of openings for the passage of rays concentrated by the collimating optical elements. A disadvantage of this design is the fact that the optical system poses high requirements for the installation space, while the light device with an exact position of individual diaphragms and collimating elements features a relatively long optical axis whose direction corresponds to that of the light axis of the vehicle x, which restricts variability of the mechanical design of the light device, e.g., the design of the arrangement of the cooling system. Shortening of the optical axis results in a reduction of the focal distance of the optical elements, which enhances variability of the mechanical design, but the impact on the emission characteristics of the resulting light trace is negative.
In the prior art, a number of projection systems are known where the display trace consists of several projection patterns. A technical problem of these projection systems is creation of a compact display area with homogeneous light intensity all over the area, since at the contact edge of two neighbouring patterns or two light functions increased light intensity, or conversely, unlit places can be observed. Another disadvantage is the fact that if a sharp transition between the lit and unlit part of the carriageway is created, the human eye concentrates on the lit part in such a way that it virtually does not see the unlit part. But if the light/darkness boundary is not sharp, the human eye is able to better perceive the unlit part of the space in front of the vehicle.
A goal of the present invention is to eliminate the above-mentioned shortcomings of the prior art. Another goal is to design a light device whose adjustment system that achieves the required emission characteristic is structurally simple and at the same time enables efficient adjustment of the optical system, while individual elements of the optical system are efficiently arranged in the inner space of the lamp in such a way that the optical system does not pose high requirements for the installation space and is adaptable to the design of the light device. Still another goal is to realize the possibility of influencing the sharp or blurred character of the light trace edges and thus the light and darkness transition, and of creating various shapes of light traces with homogeneous light intensity distribution.